Improvement in sewing-machines



WITNESSES.

2 Sheets--Sheet1. C. B. TRUE.

Sewing-Machines. N0 148,336, Patented March 10, 1874.

INVENTR.

` 2Shets--Sheet2i.

c. s. TRUE. y

. 'Sewing-Machines.

N0 ]48,336' A Y PatentedMarchl0A874.

FlCnSI WITNESEESl y INVENTURI NrrED STATES TENT man.

cYnUs B. TRUE, .orrnovmnn'en7 RHODE IsLAND.

IMPROVEMENT IN SEWING-MACHINES.

Specification forming part of Lettere Patent No. 11i-8,336. dated March 10, 1874; application filed October 14, 1873. V

To all 'whom t may concern: Beit known that I, CYRUs B. TRUE, of the city and county of Providence7 in the State of Rhode Island, have invented certain new and useful Improvements in Sewing-Machines.

My invention consists, first, in the combination of certain novel devices with a laterally and vertically vibratin g feed-bar lever, whereby the four requisite motions of the said feedbar are easily and noiselessly effected; secondly, in a novel combination, with said feedbar lever, of a longitudinally-reciprocating bar actuated by and through its connection with the main shaft, and a bell-crank lever provided with an inclined face on one of itsarms, and adjustable on its fulcrum, whereby the movement andalso to the inner coincident faces of the jaws of said lever, whereby objectionable friction of the parts in operative contact is reduced to a minimum, their operation renderedv noiseless, and theundue wear at all points readily compensated fifthly, in combining with a spring take-up a controlling-cam mounted on the main shaft, and arranged in a novel man- .ner with relation to the take-up, whereby, at the proper moment, during the movement of the needle 'bar, the slack thread will be Lproperly controlled, and also in other minor pointsto which particular reference will hereafter be made.; and I do hereby declare that the fbllowingspeciiication, taken in connection with the drawings furnished and forming a 4part thereof, is a clear, true, and accurate description yof a sewing-machine. embodying the -several features of my invention.

Although 'some of the novel elements shown are applicable to sewing-machines in general,

inany of them areA applicable only to that par- ,ticular class in which vibrating levers are ein- `'ployed for giving the requisite movement to the shuttle, and, therefore, l have selected, for the better illustration of my invention, a machine of that character.

Referring to the two sheets of drawings, Figure l represents, in side view, a machine which embodies my invention detached from the table. Fig. 2 represents the same as viewed from below. Fig. 3, Sheet 2, represents the rear of the same in end view with main shaftwheel removed. y Fig. ,4 represents a portion of the machine in front-end view with a portion of the casing removed, and showing the novel take-up mechanism. Fig. 5 shows the device for graduating the receptive capacity of the jaws of a bifurcated lever. Fig. 6 shows a portion of the main shaft, a cam thereon, and its connection with a vertically-reeiprocating bar, which actuates the feed-bar in its forward longitudinal movement. Fig. 7 shows the novel adjustable lever-ball and its sliding bearings fitted to the coincident faces of the jaw of a bifurcated lever, in this instance employed for actuating the shuttle. Fig. S shows a similar adjustable lever-ball directly fitted to the jaw of a lever. Fig. 9 shows, in perspective, the tension-plate with. its self -adj ustin g' frictionbed.

. In all the figures, A denotes the main shaft. The needle-bar, presser-bar, shuttle, and its carrier are not unlike those found in other machines of this class, and require 'no detailed description in this connection. B denotes the vertically-vibrating lever, for actuating the shuttle-lever D. It is bifurcated at its upper end and embraces an actuating-cam, c, on the mainY shaft. As the contact surfaces of the cam and the coincident faces are liable to undue wear, I have provided the adjustable facebloek C, shown in detail in Fig'. 5. The rear of the block is channeled, so as to receive the jaw and secure itf against lateral movement thereon, and. yet be capableV of adjustment longitudinally, and of being rigidly set byA means ofthe screw b and a slot in the jaw.

The face-block is thicker at one end than at the other, and, by moving it in the direction of its thinnest end, the cam on the main shaft will be more closely embraced between it and the coincident face of the jaw, and this adjustment can readily be effected by any person of competent judgment, whenever lundue wear has occurred to such anextent as to be at all perceptible in the operation of the machine. At the lower end of lever B is a ball, c, which is so divided by a slot, in a line with the axis of the lever, that the two sections may be forced apart by the advancing of a conical screw, d, or any equivalent device introduced between the sections, and having the function of a wedge. The depth of the slot toward the axis or pivoted fulcrum of the lever should be suicient to admit of the proper separation of the sections, and of their resuming their normal position on the withdrawal of the spreading device. As the contact surfaces become worn a slight advancing of the expanding device will bring the parts into close relation, and obviate all lost motion. As shown in Fig. 7, the two concave sliding bearings 4c are iitted with their outer sides to the plane interior faces of the jaws. Their inner sides are concave to receive the sides of the ball, as shown. In operation there is a slight movement of the bearings longitudinally in the jaw, and they are free, in other respects, to follow the movement of the ball. The depth of the concavity in each is suficient to hold them in proper position when the ball is properly expanded. E denotes the four motion feed-bar. Its downward and retreating movements are effected by a compound spring, e, composed of a singleV piece of spring-wire, so bent as to present two straight arms extending from opposite sides of a complete coil. The outer end of one of the arms is rigidly fixed to a lug or ear on the under side of the bedplate, and the outer end of the other arm engages with the feed bar. The backward movement" of the feed-bar is effected by the expansive force of the arms of the spring, and the downward movement by the retractile force of the coiled portion thereof. F denotes the feed-bar lever. It is provided with a complex fulcrum, composed of two axes, 011e of which is vertical and the other is horizontal and at right angles thereto. The lever is secured to the under side of the bed-plate by a screw, f, which constitutes the vertical fulcrum. The screw f is inclosed by a sleeve or bushing provided with a trunnion on each side, which constitute the horizontal fulcrum, and this complex fulcrum admits of a horizontal or laterally vibratory and a vertically-vibrating movement of the lever. 'lhe lever and feed-bar are connected, as at g, with a screw, which is snugly fitted to a tappedhole in the lower edge of the feed-bar. The screw-hole in the lever is round and well tted to the body of the screw. l To compensate for undue wear at this point, an oval steel bushing may be fitted to the body of the screw, having sufficient length thereon to admit of its contact, at its ends, with the under side of the head and the surface of the feed-bar, and so be held in any position. Whenever required, the bushing maybe slightly turned on the screw, and made to occupy any space resulting from undue wear of the parts. The opposite end of the feedbar lever is lprovided with a vertical slot, as' at h, for the reception of the vertically-reciprocating bar G, which is the connecting device between the cam H on the main shaft and the feed-bar lever. The upper endof the bar G is provided with a head of peculiar construction,

as shown in Fig. 6. It is vertically slotted to enable it to surround the main shaft, and be capable of avertical movement effected by the cam H, in contact with the coincident surfaces of the channel t' on one side of the head. One of the contact-surfaces may be made adjusta-` ble with relation to the other by means substantially as described, in connection with the jaws of the lever B, and thereby be capable of compensating for undue wear. The lower end of bar Gr is provided with a toe, as at k, i

which, by contact with an inclined surface, as at l, as thebar is raised, actuates the leverF,

and gives to-the feed-bar its forward movement. The surface `l is the face of the vertical w i arm of a bell-crank lever, I, which is in comface l of the bell-crank lever. This construction l and arrangement of the lever-bar G and bellcrank lever admit of compensation for undue wear of the several coincident contact-surfaces, as well as of the feed-adjustment.

I have already described the means by which the forward, backward, and downward motions of the feed-bar are effected, and it now remains to show how the upward movement is accomplished. On the side of the shuttle-lever D, adjacent to its fulcrum, is a laterally-projecting arm, K, (shown clearly in Fig; 2.) At a point on the upper side of the feed-bar lever F, midway between the fulcrum and its rear end, is a convex cam-surface atm, so located with relation to the arm K that the latter will be in contact therewith and the plane-surface on each side thereof, both toward the fulcrum and the end of the lever, at each vibration of the shuttle-lever D; and, by this movement,

it will deflect the rear end of the feed-bar lever, raise the opposite end, and thus eifect the upward movement of the feed-bar. Each of the two separate positive movements is properly timed with relation to the movement of the needle-bar, the return spring motions are promptly executed, and, as all the operative surfaces are held in close contact by the compound spring c, their operation, as a whole, is smooth, easy, and silent. L denotes the tension-plate, shown in perspective in Fig. 9. It is of the usual form, and provided with the adjusting thumb-screw n. N denotes a crankplate on the main shaft, carrying a wrist-pin, p, for operating the needle-bar, and is clearly shown in Fig. 4.- Aboutthree-quarters of its periphery is circular, and the remaining quarter is provided with a flat face, as at q,'the edge constituting al cam for controlling the take-up by a positive movement.' O denotes the take-up lever, provided with the usual thread-eye 1' at its upper end. It is composed of spring wire, and has a capacity insuflicientl to break the threads in common use under any circumstances. Its base is connected with a pivoted lever, s, the outer end of which is held in close contact with the periphery of the cam during its revolution by the retractile spiral springt, which is connected therewith by a ngeron the lever s, below and adjacent to its pivot, at the proper moment, and wholly in concert with the movement ofthe needlebar. The take-up--is alternately actuated by the cam, and operated with results analogous to those eftectedfby numerous other well-known thread-controlling devices, employing dill'ercnt mechanism;

Having thus described my invention, I claim as new, to be secured by Letters Patent--s 1. The feed-bar and spring for effecting the two distinct return movements, in combination with the vertically and laterally vibratingfeedbar lever, which is operatively connected intermittingly with the mainy shaft, so that the feed-bar will be raised and carried forward byy positive mechanical movement, and admit of the return movements ofthe feed-bar and its lever by spring action, substantially as described.

2. The combination, with a laterally-vibrating feed-bar lever, of a vertically-reciprocating bar, provided with a toe-cam, and working against an inclined face in contact with said toe, substantially as described.

3. The combination, with a laterally-vibrating feed-bar lever and a vertically-reciprocat- 'ing bar, of a bell-crank lever, with a surface `ing device,`for maintaining proper contact of the ball with the bearings, and the bearings with the coincident faces of the jaw, substantially as described.

' 6. The combination of the cam N, the elas tic spring take=up arm O, the connecting=lever s, and the spring t, for holding saidlever in contactwith the face of the cam7 and arranged to operate substantially as described.

crans B. TRUE.

Witnesses THOMAS F. CosGRoi/E, ORRIN'L. BoswoR'rH. 

